A PORTABLE wheel lathe designed for emergency field repairs to wheel damage on freight wagons was officially launched by Swedish maintenance specialist EuroMaint Rail AB at the Nordic Rail exhibition in Jönköping on last month.

EuroMaint Rail's PWL can be transported by van to a remote location and assembled by a two-person crew. Hydraulic and electric power is provided from a 50 kVA diesel generator in the service truck. The unit and support beams can be assembled in both left and right-handed positions to treat both wheels.

The rail vehicle is lifted slightly to relieve the load on the defective wheelset, which is turned by four hydraulic motors through profiled steel wheels on the wheel flanges. The wheel is first assessed with a portable measuring head to determine the diameter, out-of-roundness and the rectification work required. This data is fed into the CNC controls, and the measuring head exchanged for a cutter.

Typically, each wheel is turned twice to remove the defects and produce a new profile according to given UIC standards. A 5 mm deep radial cut can be turned at each pass. The second wheel is then treated in the same way, the whole process taking between 1 h and 2 h. Turning both wheels can generate up to 10 kg of swarf, and EuroMaint has designed the cutting process to produce small shavings rather than long spirals. A protective mat is laid under the vehicle before work starts to collect the waste and prevent any environmental damage.

The maintenance crew uses EuroMaint's portable brake testing equipment to verify the vehicle's braking performance, both to detect any fault which could have caused the wheel flat and to confirm that the rectified vehicle is fit to continue its journey. All data from both systems is transferred by GSM or GSM-R to the customer for record-keeping purposes and subsequent analysis.

According to EuroMaint's Head of Engineering Thomas Robertsson, the prototype PWL has been tested for around a year and has proved very successful, mainly in the north of Sweden where wheel flats are a common problem during the long Nordic winter. Turning the wheels in situ avoids the need to use lifting cranes when changing the wheelsets, which can be a major problem under 15 kV catenary. It also avoids the requirement to dismantle the brakes or unload the wagon, minimising handling damage and any delays to the shipment.

A second unit is due to start work in the spring of 2008, expanding the geographical coverage of EuroMaint's support service. Robertsson expects that EuroMaint Rail's PWL will be available commercially from 2009.
EuroMaint Rail AB, Sweden